1. Field of the Invention
The present invention relates to an image pickup apparatus, such as a digital camera, which includes a lens apparatus equipped with a voice coil motor (“VCM”) that is configured to move a lens in an optical axis direction.
2. Description of the Related Art
The actuator used for the lens apparatus to move a lens in the optical axis direction includes a stepping motor, a vibration type motor, a VCM, etc.
Japanese Patent Laid-Open No. (“JP”) 5-150152 discloses a lens apparatus that uses a VCM as an actuator. This lens apparatus configures the VCM by providing a coil to a lens holder that holds the lens, and a magnet that is opposite to part of the coil and extends in the optical axis direction. As the coil is supplied with current, a thrust occurs in the optical axis due to the interaction between the magnetic flux generated by the magnet and the magnetic flux generated by the coil, and drives the lens holder in the optical axis direction.
However, the VCM does not possess a magnetic or frictional stopping and maintaining power in the non-electrification state unlike the stepping motor or the vibration type motor, and thus needs a mechanism for stopping the lens holder driven by the VCM (which will be referred to as a “VCM lens holder” hereinafter), when the lens apparatus (or the image pickup apparatus provided with the lens apparatus) is powered off and the VCM becomes in the non-electrification state. This is because when the lens apparatus receives a vibration or a shock in the non-electrification state of the VCM, the VCM lens holder is likely to move and to collide with another lens holder or component, causing a collision noise or lowering an optical characteristic.
JP 2005-274631 discloses a lens apparatus that restricts a movement of the VCM lens holder in the non-electrification state of the VCM by using another lens holder that moves in the optical axis direction in association with a retraction from a usable position (image picking-up position) when the power is off.
JP 2007-033556 discloses a lens apparatus that restricts a movement of the VCM lens holder in the non-electrification state of the VCM by using a lens barrier unit that moves in the optical axis direction in association with the retraction.
These lens apparatuses disclosed in JPs 2005-274631 and 2007-033556 thus restrict a movement of the VCM lens holder by using the other lens holder or the lens barrier (collectively a “stopper” hereinafter) configured to move in the optical axis direction in association with the retraction, but have the following disadvantages: The stopper can restrict the movement of the VCM lens holder only when a moving amount of the stopper in association with the retraction is large than a moving amount of the VCM lens holder.
In other words, when the moving amount of the VCM lens holder in association with the retraction is larger than the moving amount of the other lens holder or the lens barrier unit, the other lens holder or the lens barrier unit cannot be used as the stopper.